Chestnut-backed Bluebird 527 
Eastern Bluebird. Stalia sialis. 
A.O.U. Checklist no 766—Colorado Records—Aiken 72, p. 194; 
Tresz 81, p. 284; Nash 83, p. 46; Beckham 85, p. 140; Thorne 86, p. 
489 ; Cooke 97, pp. 126, 170, 223; H. G. Smith 96, p. 76; 08, p. 191; 
Dille 00, p. 88 ; Henderson 03, p. 237; 09, p. 242. 
Description.—Male—Above bright ultramarine-blue, becoming dusky 
on the inner webs of the wing-feathers ; sides of the head dull blue ; 
below rufus-brown, white from the centre of the abdomen to the under 
tail-coverts ; iris dark brown, bill and legs black. Length 6-25; 
wing 3-80; tail 2-50; culmen -48; tarsus -75. 
The female is blueish-grey above, brightening to blue on the rump 
and tail; longer wing-feathers edged with grey or white, as is also 
the outer web of the outer primary. In the fall the bright blue of the 
male is obscured by a brownish wash. A young bird is dusky above, 
spotted and streaked with white or pale buffy; only the wings and 
tail show some blue, below dull white, the edges of the feathers marked 
with brown, producing a squamated appearance. 
Distribution.—Breeding from Montana, Manitoba and Nova Scotia, 
south to Florida and Texas; wintering in the southern half of its 
breeding range. 
The Eastern Bluebird is by no means an uncommon summer resident 
on the eastern plains of Colorado, and has even been found nesting 
in the foothills of Boulder co. by Gale (Cooke). It was first definitely 
recorded from the State by Holden, who took a specimen near 
Fountain, El Paso co. (Aiken). It has since been noticed at Julesburg, 
Wray, Kit Carson, Holly and Prowers, along the eastern borders of 
the State by Smith (08) and Ferrill, and at Limon by Aiken, while 
Dille found it nesting at Denver, and Thorne at Fort Lyon. It arrives 
in April—Pueblo, April 6th, Nash; and has been seen as late as 
September 6th at Denver, by H. G. Smith (96). 
Habits.—A nest found by Dille was built in a nest- 
box which had been used by the Arctic Bluebird pre- 
viously the same season. A clutch of five eggs was 
taken on June 21st; Gale’s nest contained four fresh 
eggs on June 18th, and was found on a ranch near Gold 
Hill, in Boulder co. 
Chestnut-backed Bluebird. Sialia mexicana batrdi. 
A.O.U. Checklist no 767a—Colorado Records—Allen 72, p. 148; 
Aiken 72, p. 194 ; Trippe 74, p. 229 ; Tresz 81, p. 284; Allen & Brewster 
83, p. 153 ; Drew 85, p. 15 ; Beckham 85, p. 140; 87, p. 125 ; Morrison 
